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Characteristics of an early Holocene climate and environment from lake sediments in Ebinur region, NW China

Science China Earth Sciences 2005年第2期48卷 258-265页

作者： WU Jinglu SHEN Ji WANG Sumin JIN Zhangdong YANG Xiangdong Nanjing Institute of Geography & Limnology Chinese Academy of SciencesNanjing210008China Nanjing Institute of Geography & LimnologyChinese Academy of SciencesNanjing210008China Nanjing Institute of Geography & LimnologyChinese Academy of SciencesNanjing210008China Nanjing Institute of Geography & LimnologyChinese Academy of SciencesNanjing210008China Nanjing Institute of Geography & LimnologyChinese Academy of SciencesNanjing210008China

The characteristics of climatic environment in the early Holocene epoch were studied through analyzing environmental proxies from the sediments in the Ebinur Lake--a closed one in the arid region. The pollen assemblage and other geochemical indices showed that, the temperature was somewhat low in the period (8.0-11.5 cal kaBP) as a whole, but in the early period (11.5-10.6 cal kaBP) the temperature was higher, in company with more precipitation. In the conversion period from the early Holocene epoch to the middle Holocene epoch (8.9-8.0 cal kaBP) the climate fluctuated remarkably. Particularly the three layers of peat sediment revealed the strong instability of climate in the early Holocene epoch in the Ebinur region. All information on the development of peat and the experimental data of pollen and stable isotopes implied that, the climatic condition at 8.2, 8.6 and 10.5 cal kaBP was characterized by noticeable cold and humidness, and could be regarded as three cold and humid events in the early Holocene epoch.

关键词： early Holocene epoch, climatic evolution, pollen assemblege, stable isotopic record, Ebinur Lake.

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Zircon and apatite fission track analyses on mineralization ages and tectonic activities of Tuwu-Yandong porphyry copper deposit in northern Xinjiang, China

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Science China Earth Sciences 2007年第12期50卷 1787-1795页

作者： YUAN WanMing1,BAO ZengKuan2,DONG JinQuan2,GUO ZhaoJie3 & DENG Jun1 1 State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Beijing100083,China 2 Laboratory of Nuclear Analysis Techniques,Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100039,China 3 Department of Geology,Peking University,Beijing 100871,China State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing China Laboratory of Nuclear Analysis Techniques Institute of High Energy Physics Chinese Academy of Sciences Beijing China Department of Geology Peking University Beijing China

The mineralization ages reported in the past in the Tuwu-Yandong copper district not only are different,but also fall into the Hercynian *** study has achieved 9 zircon and 7 apatite fission track analysis *** zircon fission track ages range from 158 Ma to 289 Ma and the apatite ages are between 64 Ma and 140 *** mineralization accords with the regional tectonics in the copper *** consider that the zircon fission track age could reveal the mineralization age based on annealing zone temperature of 140―300℃ and retention temperature of ～250℃ for zircon fission track,and metallogenetic temperature of 120―350℃ in this ore *** three mineralization epochs have been identified,i.e.,289―276 Ma,232―200 Ma and 165―158 Ma,and indicate occurrence of the min-eralization in the Indosinian and Yanshan *** to apatite fission track ages,the three tectonic-mineralizing epochs are 140―132 Ma,109―97 Ma and 64 Ma,which means age at about 100℃ after the *** three epochs lasted 146 Ma,108 Ma and about 100 Ma from ～250℃ to ～100℃ and trend decrease from early to *** is shown by the fission track modeling that this district underwent three stages of geological thermal histories,stable in Cretaceous and cooling both before Cretaceous and after 20 Ma.

关键词： mineralization age, tectonic epoch, fission track, zircon, apatite, Tuwu-Yandong, Xinjiang

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